Polylactide based compositions

ABSTRACT

Embodiments of poly-lactide compositions are disclosed herein. The compositions may comprise at least one first polymer selected from polylactide-polybutadiene (PLA-PB) block copolymer, polylactide-urethane-polybutadiene block copolymer, or a mixture thereof; and at least one second polymer selected from polylactide, polylactide-urethane, or a mixture thereof. The composition may also comprise from 20% to 50% by weight of said first polymer based on the total weight of the composition and from 50% to 80% by weight of said second polymer based on the total weight of the composition. Embodiments of the present invention also relate to a process for preparing the poly-lactide compositions and articles comprising the poly-lactide compositions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/306,810, filed Oct. 26, 2016, which claims the benefit ofPCT/EP2015/059244, filed Apr. 28, 2015, which claims priority from EP14166458.1, filed Apr. 29, 2014, which are incorporated herein in theirentireties for all purposes.

FIELD OF THE INVENTION

The invention pertains to a composition comprising a polylactide-basedpolymer, and the use thereof.

BACKGROUND OF THE INVENTION

Polylactide also referred as polylactic acid (PLA) is a syntheticaliphatic polyester derived from renewal resources, such a corn, sugarbeet and cassava, which can ultimately be degraded under compostingconditions.

Although attempts have been made to utilize PLA for various end-useapplications, PLA is known to be brittle and exhibit low toughness,which can result in low impact strength products or articles. Impactresistance of PLA can be modified by using existing polymeric impactmodifiers; however, currently available polymeric impact modifiersalways decrease transparency of PLA material. A liquid plasticizer canbe used at high content (>15%) to improve impact resistance of PLA,however during the life time of the PLA blend, there is migration of theplasticizer.

Impact modifiers such as rubber, poly(ethylene glycol) (PEG), andacrylonitrile-butadiene-styrene copolymer (ABS) have been tested.Nevertheless, the immiscibility between these impact modifying additivesand the PLA matrix is a major drawback.

Commercially available BioStrength® 150 a methylmethacrylate-butadiene-styrene co-polymer (MBS) is one of the bestcurrently available impact modifiers for PLA; however haze of theresulting PLA material increases from 5, for pure PLA to 95 when 15% w/wof BioStrength® 150 is added. Another commercial product, BioStrength®280, an acrylic core shell impact modifier, is a less efficient impactmodifier, although the resulting PLA material is said to remaintransparent. Nevertheless, the present inventors observed that additionof 15% w/w of BioStrength® 280 produces a material with a haze of 44.

Plasticizers are additives that increase the fluidity of a material.Commonly used plasticizers, are tributyl citrate (TBC) and acetyltributyl citrate (ATBC). However, when 15% TBC or ATBC were mixed withPLA, the present inventors observed a plasticizer migration afterstorage for a few days at room temperature in summer time (25-30° C.).

Other commonly used polymer modifiers are styrene block copolymers, suchas poly(styrene-butadiene-styrene), or SBS. Further studies performed bythe present inventors, showed that a blend of PLA with SBS exhibited atotal incompatibility even at a concentration as low as 10% w/w of SBS.

There is therefore a need to improve the compositions of the prior art.

SUMMARY OF THE INVENTION

Surprisingly it has been discovered that polylactide-polybutadiene(PLA-PB) block copolymer, or polylactide-urethane-polybutadiene blockcopolymer, or mixture thereof, increases significantly the impactproperties of PLA based composition in comparison to polylactide basedcomposition alone, or with standard impact modifiers.

It has been also discovered that compositions comprising at least onePLA based polymer and polylactide-polybutadiene (PLA-PB) blockcopolymer, or polylactide-urethane-polybutadiene block copolymer, ormixture thereof, have a better impact performance than the samecompositions with standard impact modifiers. The compositions have alsoimproved transparency, while keeping other properties such asprocessing.

A first aspect of the present invention provides a compositioncomprising:

(a) at least one first polymer selected from polylactide-polybutadiene(PLA-PB) block copolymer, polylactide-urethane-polybutadiene blockcopolymer, or a mixture thereof; and

(b) at least one second polymer selected from polylactide,polylactide-urethane, or a mixture thereof. Preferably, the compositioncomprises from 20% to 50% by weight of said first polymer based on thetotal weight of the composition and from 50% to 80% by weight of saidsecond polymer based on the total weight of the composition.

The present inventors have surprisingly found that it is possible toproduce composition having improved melt strength, and impact.

A second aspect of the present invention encompasses a process forpreparing a composition according to the first aspect of the invention,said process comprising the step of contacting (a) at least one firstpolymer selected from polylactide-polybutadiene (PLA-PB) blockcopolymer, polylactide-urethane-polybutadiene block copolymer, or amixture thereof; with (b) at least one second polymer selected frompolylactide, polylactide-urethane, or a mixture thereof.

A third aspect of the invention encompasses an article comprising acomposition according to the first aspect of the invention, or preparedusing a process according to the second aspect of the invention.

A fourth aspect of the invention encompasses the use ofpolylactide-polybutadiene (PLA-PB) block copolymer, orpolylactide-urethane-polybutadiene block copolymer, or a mixture thereofas impact modifier. The inventors have surprisingly shown that whenpolylactide-polybutadiene (PLA-PB) block copolymer, orpolylactide-urethane-polybutadiene block copolymer were used as impactmodifier, the composition containing said modifiers displayed betterperformance.

By better performance is meant that the impact modifier performs eitherbetter in terms of the impact strength used at the same quantity as thenowadays-available standard impact modifiers or the same impact strengthis obtained by incorporating a less quantity of the impact modifier incomparison the nowadays-available standard impact modifiers in athermoplastic resin, while keeping other characteristics.

The above and other characteristics, features and advantages of thepresent invention will become apparent from the following detaileddescription, taken in conjunction with the accompanying drawings, whichillustrate, by way of example, the principles of the invention. Thereference FIGURES quoted below refer to the attached drawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 represents a graph showing the DSC profile of composition 2according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

When describing the invention, the terms used are to be construed inaccordance with the following definitions, unless a context dictatesotherwise.

Unless otherwise defined, all terms used in disclosing the invention,including technical and scientific terms, have the meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. By means of further guidance, term definitions are included tobetter appreciate the teaching of the present invention.

In the following passages, different aspects of the invention aredefined in more detail. Each aspect so defined may be combined with anyother aspect or aspects unless clearly indicated to the contrary. Inparticular, any feature indicated as being preferred or advantageous maybe combined with any other feature or features indicated as beingpreferred or advantageous.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the present invention. Thus, appearances of the phrases“in one embodiment” or “in an embodiment” in various places throughoutthis specification are not necessarily all referring to the sameembodiment, but may. Furthermore, the particular features, structures orcharacteristics may be combined in any suitable manner, as would beapparent to a person skilled in the art from this disclosure, in one ormore embodiments. Furthermore, while some embodiments described hereininclude some but not other features included in other embodiments,combinations of features of different embodiments are meant to be withinthe scope of the invention, and form different embodiments, as would beunderstood by those in the art.

The terms “comprising”, “comprises” and “comprised of” as used hereinare synonymous with “including”, “includes” or “containing”, “contains”,and are inclusive or open-ended and do not exclude additional,non-recited members, elements or method steps. It will be appreciatedthat the terms “comprising”, “comprises” and “comprised of” as usedherein comprise the terms “consisting of”, “consists” and “consists of”.

As used in the specification and the appended claims, the singular forms“a”, “an,” and “the” include plural referents unless the context clearlydictates otherwise. By way of example, “a layer” means one layer or morethan one layer.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart. All publications referenced herein are incorporated by referencethereto.

The recitation of numerical ranges by endpoints includes all integernumbers and, where appropriate, fractions subsumed within that range(e.g. 1 to 5 can include 1, 2, 3, 4 when referring to, for example, anumber of elements, and can also include 1.5, 2.0, 2.75 and 3.80, whenreferring to, for example, measurements). The recitation of end pointsalso includes the end point values themselves (e.g. from 1.0 to 5.0includes both 1.0 and 5.0). Any numerical range recited herein isintended to include all sub-ranges subsumed therein.

Whenever the term “substituted” is used in the present invention, it ismeant to indicate that one or more hydrogens on the atom indicated inthe expression using “substituted” is replaced with a selection from theindicated group, provided that the indicated atom's normal valency isnot exceeded, and that the substitution results in a chemically stablecompound, i.e. a compound that is sufficiently robust to surviveisolation to a useful degree of purity from a reaction mixture. Suitablesubstituents can be selected from C₁₋₆alkyl, halogen, hydroxy,C₁₋₆alkoxy.

The term “C₁₋₂₀alkyl”, as a group or part of a group, refers to ahydrocarbyl radical of Formula C_(n)H_(2n+1) wherein n is a numberranging from 1 to 20. Generally, the alkyl groups comprise from 1 to 20carbon atoms, preferably from 1 to 12 carbon atoms, preferably from 1 to10 carbon atoms, preferably from 1 to 6 carbon atoms, more preferably 1,2, 3, 4, 5, 6 carbon atoms. Alkyl groups may be linear, or branched andmay be substituted as indicated herein. When a subscript is used hereinfollowing a carbon atom, the subscript refers to the number of carbonatoms that the named group may contain. Thus, for example, C₁₋₂₀alkylgroups include all linear, or branched alkyl groups having 1 to 20carbon atoms, and thus includes for example methyl, ethyl, n-propyl,i-propyl, 2-methyl-ethyl, butyl and its isomers (e.g. n-butyl, i-butyland t-butyl); pentyl and its isomers, hexyl and its isomers, heptyl andits isomers, octyl and its isomers, nonyl and its isomers, decyl and itsisomers, undecyl and its isomers, dodecyl and its isomers, tridecyl andits isomers, tetradecyl and its isomers, pentadecyl and its isomers,hexadecyl and its isomers, heptadecyl and its isomers, octadecyl and itsisomers, nonadecyl and its isomers, icosyl and its isomers, and thelike. For example, C₁₋₁₀alkyl includes all linear, or branched alkylgroups having 1 to 10 carbon atoms, and thus includes for examplemethyl, ethyl, n-propyl, i-propyl, 2-methyl-ethyl, butyl and its isomers(e.g. n-butyl, i-butyl and t-butyl); pentyl and its isomers, hexyl andits isomers, heptyl and its isomers, octyl and its isomers, nonyl andits isomers, decyl and its isomers and the like. For example, C₁₋₆alkylincludes all linear, or branched alkyl groups having 1 to 6 carbonatoms, and thus includes for example methyl, ethyl, n-propyl, i-propyl,2-methyl-ethyl, butyl and its isomers (e.g. n-butyl, i-butyl andt-butyl); pentyl and its isomers, hexyl and its isomers. When the suffix“ene” is used in conjunction with an alkyl group, i.e. “alkylene”, thisis intended to mean the alkyl group as defined herein having two singlebonds as points of attachment to other groups.

The term “C₁₋₆alkoxy” or “C₁₋₆alkyloxy”, as a group or part of a group,refers to a group having the Formula —OR^(a) wherein R^(a) is C₁₋₆alkyl.Non-limiting examples of suitable C₁₋₆alkoxy include methoxy, ethoxy,propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy,pentyloxy and hexyloxy.

The term “C₃₋₆cycloalkyl”, as a group or part of a group, refers to acyclic alkyl group, that is to say, a monovalent, saturated, hydrocarbylgroup having 1 or more cyclic structure, and comprising from 3 to 9carbon atoms, more preferably from 3 to 8 carbon atoms, more preferablyfrom 3 to 6 carbon atoms, still more preferably from 5 to 6 carbonatoms. Cycloalkyl includes all saturated hydrocarbon groups containing 1or more rings, including monocyclic or bicyclic groups. The furtherrings of multi-ring cycloalkyls may be either fused, bridged and/orjoined through one or more spiro atoms. Examples of C₃₋₆cycloalkylgroups include but are not limited to cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl. When the suffix “ene” is used in conjunctionwith a cycloalkyl group, i.e. cycloalkylene, this is intended to meanthe cycloalkyl group as defined herein having two single bonds as pointsof attachment to other groups.

The term “C₆₋₃₀aryl”, as a group or part of a group, refers to apolyunsaturated, aromatic hydrocarbyl group having a single ring (i.e.phenyl) or multiple aromatic rings fused together (e.g. naphthalene), orlinked covalently, typically containing 6 to 30 atoms; wherein at leastone ring is aromatic. Examples of suitable aryl include C₆₋₁₂aryl, morepreferably C₆₋₁₀aryl. Non-limiting examples of C₆₋₁₂aryl comprisephenyl, biphenylyl, biphenylenyl, or 1- or 2-naphthanelyl. When thesuffix “ene” is used in conjunction with an aryl group, this is intendedto mean the aryl group as defined herein having two single bonds aspoints of attachment to other groups.

The term “halo” or “halogen”, as a group or part of a group, is genericfor fluoro, chloro, bromo or iodo.

The term “hydroxyl” or “hydroxy”, as a group or part of a group, refersto the group —OH. The terms described above and others used in thespecification are well understood to those in the art.

Preferred statements (features) and embodiments of the compositions,polymers, processes, articles, and uses of this invention are set hereinbelow. Each statement and embodiment of the invention so defined may becombined with any other statement and/or embodiment, unless clearlyindicated to the contrary. In particular, any feature indicated as beingpreferred or advantageous may be combined with any other features orstatements indicated as being preferred or advantageous. Hereto, thepresent invention is in particular captured by any one or anycombination of one or more of the below numbered aspects and embodiments1 to 21, with any other statement and/or embodiment.

1. A composition comprising:

(a) at least one first polymer selected from polylactide-polybutadiene(PLA-PB) block copolymer, polylactide-urethane-polybutadiene blockcopolymer, or a mixture thereof; and

(b) at least one second polymer selected from polylactide,polylactide-urethane, or a mixture thereof.

2. A composition comprising:

(a) at least one first polymer selected from polylactide-polybutadiene(PLA-PB) block copolymer, polylactide-urethane-polybutadiene blockcopolymer, or a mixture thereof; and

(b) at least one second polymer selected from polylactide,polylactide-urethane, or a mixture thereof;

wherein the composition comprises from 20% to 50% by weight of saidfirst polymer based on the total weight of the composition and from 50%to 80% by weight of said second polymer based on the total weight of thecomposition

3. The composition according to statement 1 or 2, wherein the at leastone first polymer is polylactide-polybutadiene (PLA-PB) block copolymerand the at least one second polymer is selected from polylactide.

4. The composition according to any one of statements 1 to 3, whereinthe at least one first polymer is poly-L-lactide-polybutadiene (PLLA-PB)block copolymer and the at least one second polymer is selected frompoly-L-lactide.

5. The composition according to any one of statements 1 to 4, whereinsaid polylactide-polybutadiene (PLA-PB) block copolymer is selected fromthe group comprising PLA-PB diblock copolymer, PLA-PB-PLA triblockcopolymer, PLA-PB multiblock copolymer, PLA-PB star copolymers, PLA-PBcomb copolymers, PLA-PB gradient containing block copolymers; andmixtures thereof.

6. The composition according to any one of statements 1, 3 to 5, whereinsaid composition comprises from 1 to 60% by weight of said first polymerbased on the total weight of the composition; preferably, saidcomposition comprises from 2 to 55% by weight of said first polymerbased on the total weight of the composition.

7. The composition according to any one of statements 1, 3 to 6, whereinsaid composition comprises from 40 to 99% by weight of said secondpolymer based on the total weight of the composition.

8. The composition according to any one of statements 1, 3 to 7,comprising from 1% to 60% by weight of polylactide-polybutadiene blockcopolymer based on the total weight of the composition; and from 40% to99% by weight of the second polymer (b) based on the total weight of thecomposition.

9. The composition according to any one of statements 1, 3 to 8,comprising from 1% to 60% by weight of polylactide-polybutadiene blockcopolymer based on the total weight of the composition; and from 40% to99% by weight of polylactide (b) based on the total weight of thecomposition.

10. The composition according to any one of statements 1 to 9, whereinsaid composition is obtained by melt blending the at least one firstpolymer with the at least one second polymer

11. The composition according to any one of statements 1 to 10,comprising from 25% to 50% by weight of polylactide-polybutadiene blockcopolymer based on the total weight of the composition; and from 50% to75% by weight of the second polymer (b) based on the total weight of thecomposition.

12. The composition according to any one of statements 1 to 11,comprising from 25% to 50% by weight of polylactide-polybutadiene blockcopolymer based on the total weight of the composition; and from 50% to75% by weight of polylactide (b) based on the total weight of thecomposition.

13. A process for preparing a composition according to any one ofstatements 1 to 12 comprising the step of

contacting (a) at least one first polymer selected frompolylactide-polybutadiene (PLA-PB) block copolymer,polylactide-urethane-polybutadiene block copolymer, or a mixturethereof; with (b) at least one second polymer selected from polylactide,polylactide-urethane, or a mixture thereof.

14. A process for preparing a composition according to any one ofstatements 1 to 12 comprising the step of

contacting (a) at least one first polymer selected frompolylactide-polybutadiene (PLA-PB) block copolymer,polylactide-urethane-polybutadiene block copolymer, or a mixturethereof;

with (b) at least one second polymer selected from polylactide,polylactide-urethane, or a mixture thereof;

wherein the composition comprises from 20% to 50% by weight of saidfirst polymer based on the total weight of the composition and from 50%to 80% by weight of said second polymer based on the total weight of thecomposition.

15. The process according to statement 13 or 14, wherein said contactingstep comprises melt blending the at least one first polymer with the atleast one second polymer.

16. The process according to any one of statements 13 to 15, whereinsaid composition is melt blended at a temperature ranging from 160° C.to 230° C., preferably at a temperature ranging from 160° C.-200° C.

17. The process according to any one of statements 13 to 16, comprisingmelt processing a blend comprising polylactide-polybutadiene (PLA-PB)block copolymer and poly-lactide.

18. The process according to any one of statements 13 to 17, comprisingmelt blending from 25% to 50% by weight of polylactide-polybutadieneblock copolymer; and from 50% to 75% by weight of polylactide.

19. The process according to any one of statements 13 to 18, furthercomprising processing the composition using one or more polymerprocessing techniques selected from film, sheet, pipe and fiberextrusion or coextrusion; blow molding; injection molding; rotarymolding; foaming; and thermoforming.

20. An article comprising a composition according to any one ofstatements 1 to 12, or formed using a process according to any one ofstatements 13 to 19.

21. Use of polylactide-polybutadiene (PLA-PB) block copolymer,polylactide-urethane-polybutadiene block copolymer, or mixtures thereofas impact modifier.

According to the first aspect, a composition is provided comprising:

(a) at least one first polymer selected from polylactide-polybutadiene(PLA-PB) block copolymer, polylactide-urethane-polybutadiene blockcopolymer, or a mixture thereof; and

(b) at least one second polymer selected from polylactide,polylactide-urethane, or a mixture thereof. In a preferred embodiment,the composition comprises from 20% to 50% by weight of said firstpolymer based on the total weight of the composition and from 50% to 80%by weight of said second polymer based on the total weight of thecomposition.

Preferably, according to the first aspect, a composition is providedcomprising

(a) polylactide-polybutadiene (PLA-PB) block copolymer; and

(b) at least one second polymer selected from polylactide,polylactide-urethane, or a mixture thereof.

Preferably, the composition comprises: (a) polylactide-polybutadiene(PLA-PB) block copolymer; and (b) polylactide.

For example, the composition can comprise:

(a1) at least one first polymer selected from the group comprisingpoly-L-lactide-polybutadiene (PLLA-PB) block copolymer,poly-D-lactide-polybutadiene (PDLA-PB) block copolymer,poly-DL-lactide-polybutadiene (PDLLA-PB) block copolymer,poly(meso)-lactide-polybutadiene block copolymer,poly-L-lactide-urethane-polybutadiene (PLLA-PB) block copolymer,poly-D-lactide-urethane-polybutadiene (PDLA-PB) block copolymer,poly-DL-lactide-urethane-polybutadiene (PDLLA-PB) block copolymer,poly(meso)-lactide-urethane-polybutadiene block copolymer, and mixturethereof, and

(b1) at least one second polymer selected from the group comprisingpoly-L-lactide, poly-D-lactide, poly-DL-lactide, poly-meso-lactide, andmixture thereof.

The present composition comprises (a) at least one first polymerselected from polylactide-polybutadiene (PLA-PB) block copolymer,polylactide-urethane-polybutadiene block copolymer, or a mixturethereof.

The first polymer is a block copolymer. Suitable block copolymercomprises polymer comprising multiple sequences, or blocks, of the samemonomer alternating in series with different monomer blocks; theseblocks are covalently bound to each other. Block copolymers are normallyprepared by controlled polymerization of one monomer, followed by chainextension with a different monomer. Block copolymers are classifiedbased on the number of blocks they contain and how the blocks arearranged. For example, block copolymers with two blocks are calleddiblocks; those with three blocks are triblocks; and those with morethan three are generically called multiblocks. Classifications byarrangement include the linear, or end-to-end, arrangement and the stararrangement, in which one polymer is the base for multiple branches.

In an embodiment, said block copolymer is selected from diblockcopolymer, triblock copolymer, multiblock copolymer, star copolymers,comb copolymers, gradient containing block copolymers, and othercopolymers having a blocky structure, which will be known by thoseskilled in the art. Preferred are diblock and triblock copolymers. Anexample of a gradient containing block copolymer is when the monomer ormonomers used from one segment are allowed to further react as a minorcomponent in the next sequential segment. For example, if the monomermix used for the 1st block (A block) of an AB diblock copolymer ispolymerized to only 80% conversion, then the remaining 20% of theunreacted monomer is allowed to react with the new monomers added forthe B block segment, the result is an AB diblock copolymer in which theB segment contains a gradient of the A segment composition. The term“comb copolymer,” as used herein, describes a type of graft copolymer,wherein the polymeric backbone of the graft copolymer is linear, oressentially linear and is made of one polymer A, and each side chain(graft segment) of the graft copolymer is formed by a polymer B that isgrafted to the polymer A backbone. Used herein, the terms “combcopolymer” and “graft copolymer” have the same meaning.

In an embodiment, said polylactide-polybutadiene (PLA-PB) blockcopolymer is selected from the group comprising PLA-PB diblockcopolymer, PLA-PB-PLA triblock copolymer, PLA-PB multiblock copolymer,PLA-PB star copolymers, PLA-PB comb copolymers, and PLA-PB gradientcontaining block copolymers. Preferable diblock and triblock copolymersinclude PLA-PB and PLA-PB-PLA block copolymers.

In an embodiment, the polylactide-polybutadiene block copolymer isproduced by combining a lactide (such as L-lactide, D-lactide,LD-lactide, meso-lactide or mixture thereof with a polybutadiene,preferably a hydroxy functionalized polybutadiene. Lactide includesL-lactide, which is a cyclic dimer of L-lactic acid (also referred as“L-L-lactide” or “(S,S)-lactide”=cyclic di-ester of two lactic acid Senantiomers); D-lactide, which is a cyclic dimer of D-lactic acid (alsoreferred as “D-D-lactide” or “(R,R)-lactide”=cyclic di-ester of twolactic acid R enantiomers); meso-lactide, which is a cyclic dimer ofD-lactic acid and L-lactic acid; and DL-lactide, which is a racemate ofD-lactide and L-lactide. In a preferred embodiment, thepolylactide-polybutadiene block copolymer is produced by combining alactide selected from the group comprising L-lactide, D-lactide,LD-lactide, meso-lactide or a mixture thereof with a polybutadiene,preferably a hydroxy functionalized polybutadiene. In one or moreembodiments, the block copolymer is produced by melt blending a lactideand a hydroxy functionalized polybutadiene. Such processes may utilizecatalysts for polylactic acid formation, such as tin compounds (e.g.,tin octylate), titanium compounds (e.g., tetraisopropyl titanate),zirconium compounds (e.g., zirconium isopropoxide), antimony compounds(e.g., antimony trioxide) or combinations thereof, for example.

In some embodiments, it can be desirable to use lactide stereochemistryDD or LL having an optical purity also called isomeric purity L- or D ofat least 70% by weight, for example at least 80%, for example at least90%, for example at least 95%, for example at least 98% by weight.

Among the hydroxyl-terminated polybutadienes that are useful forpreparing the block copolymers are those possessing a number averagemolecular weight (Mn) of at least 1000 g/mol, for example at least 5000g/mol, preferably at least 10000 g/mol. In some embodiments thehydroxyl-terminated polybutadienes possess a Mn ranging from 1000 to20000 g/mol, for example from 5000 to 25000 g/mol, and advantageouslyfrom 8000 to 20000 g/mol, and advantageously from 9000 to 20000 g/mol,and advantageously from 10000 to 20000 g/mol.

Among the hydroxyl-terminated polybutadienes that are useful forpreparing the block copolymers are those possessing a hydroxyl groupcontent of from 0.10 to 3.0 Mmol/g.

Hydroxyl-terminated polybutadienes of the above-described type,averaging more than one predominantly primary hydroxyl group permolecule, e.g., averaging from 1.5 to 3 or more primary hydroxyl groupsper molecule, can be suitably employed herein. Branchedhydroxyl-terminated polybutadienes can possess an average of at least1.90, and advantageously from 1.95 up to 2.8 hydroxyl groups permolecule, the hydroxyl groups being predominantly in terminal positionson the main, i.e., the terminal hydroxyl groups of the polymer, arebonded to carbon atoms adjacent to double bonded carbon atoms.

The useful hydroxyl-terminated polybutadienes herein can alsoincorporate one or more other copolymerizable monomers that can conferparticularly desirable properties upon the copolymers herein and thecompositions prepared therewith. Included among the copolymerizablemonomers are mono-olefins and dienes such as ethylene, propylene,1-butene, isoprene, chloroprene, 2,3-methyl-1,3-butadiene,1,4-pentadiene, etc., and, ethylenically unsaturated monomers such asacrylonitrile, methacrylonitrile, methylstyrene, methyl acrylate, methylmethacrylate, vinyl acetate, isocyanate, etc. Alternatively or inaddition thereto, the hydroxyl-terminated polybutadienes can be reactedwith one or more other monomers to provide hydroxyl-terminated blockcopolymers. Such monomers include 1,2-epoxides such as ethylene oxideand propylene oxide which will provide polyether segments,e-caprolactone which will provide polyester segments, and the like.

Hydroxyl-terminated polybutadienes possessing these characteristics arecommercially available from several sources and are thereforeconveniently employed herein.

Examples of suitable hydroxyl-terminated polybutadiene include but arenot limited to Krasol® LBH 10000, Krasol® LBH 2000, Krasol® LBH 3000 andKrasol® LBH 5000, Krasol® LBH-P 2000, Krasol® LBH-P 3000, Krasol® LBH-P5000, Poly Bd® R45HTLO, Poly Bd® R2OLM commercially available from HSCCray Valley Corp., as well as the epoxidized hydroxyl-terminatedpolybutadiene such as Poly bd® 605 and Poly bd® 600 commerciallyavailable from HSC Cray Valley Corp.

In an embodiment, said block copolymer comprises at least 10% by weightof hydroxyl functionalized polybutadiene based on the total weight ofthe block copolymer. In an embodiment, said block copolymer comprisesfrom 10% to 90% by weight of hydroxyl functionalized polybutadiene basedon the total weight of the block copolymer.

The present invention is directed towards the use of such blockcopolymers (a) as impact modifier to improve the impact strength of thesecond polymer (b).

In some embodiments, the composition may comprise from 1 to 60% byweight of said first polymer (a) based on the total weight of thecomposition; for example from 1% to 55% by weight, for example from 2%to 55% by weight, for example from 2% to 50% by weight, for example from3% to 50% by weight, for example from 4% to 55% by weight, for examplefrom 4% to 50% by weight, for example from 5% to 55% by weight, forexample preferably from 5% to 52% by weight, for example from 5% to 50%by weight, for example preferably from 10% to 55% by weight, for examplefrom 10% to 50% by weight, preferably from 15% to 55% by weight of saidat least one first polymer (a) based on the total weight of thecomposition.

In a preferred embodiment, the composition comprises from 20% to 50% byweight, for example from 20% to 45% by weight, for example from 25% to50% by weight, for example from 25% to 45% by weight of said at leastone first polymer (a) based on the total weight of the composition.

In an embodiment, said at least one first polymer (a) ispolylactide-polybutadiene (PLA-PB) block copolymer and the at least onesecond polymer (b) is polylactide, preferably wherein the compositioncomprises 1 to 60% by weight of said first polymer (a) based on thetotal weight of the composition; for example from 1% to 55% by weight,for example from 2% to 55% by weight, for example from 2% to 50% byweight, for example from 3% to 50% by weight, for example from 4% to 55%by weight, for example from 4% to 50% by weight, for example from 5% to55% by weight, for example preferably from 5% to 52% by weight, forexample from 5% to 50% by weight, for example preferably from 10% to 55%by weight, for example from 10% to 50% by weight, preferably from 15% to55% by weight, for example from 20% to 55% by weight of said at leastone first polymer (a) based on the total weight of the composition.

In a preferred embodiment, the composition comprises from 20% to 50% byweight, for example from 20% to 45% by weight, for example from 25% to50% by weight, for example from 25% to 45% by weight of said at leastone first polymer (a) based on the total weight of the composition.

In an embodiment, said at least one first polymer (a) ispoly-L-lactide-polybutadiene (PLLA-PB) block copolymer and the at leastone second polymer (b) is poly-L-lactide, preferably wherein thecomposition comprises 1 to 60% by weight of said first polymer (a) basedon the total weight of the composition; for example from 1% to 55% byweight, for example from 2% to 55% by weight, for example from 2% to 50%by weight, for example from 3% to 50% by weight, for example from 4% to55% by weight, for example from 4% to 50% by weight, for example from 5%to 55% by weight, for example preferably from 5% to 52% by weight, forexample from 5% to 50% by weight, for example preferably from 10% to 55%by weight, for example from 10% to 50% by weight, preferably from 15% to55% by weight, for example from 20% to 55% by weight of said at leastone first polymer (a) based on the total weight of the composition.

In a preferred embodiment, said at least one first polymer (a) ispoly-L-lactide-polybutadiene (PLLA-PB) block copolymer and the at leastone second polymer (b) is poly-L-lactide, and the composition comprises20% to 50% by weight, for example from 20% to 45% by weight, for examplefrom 25% to 50% by weight, for example from 25% to 45% by weight of saidat least one first polymer (a) based on the total weight of thecomposition.

In an embodiment, said at least one first polymer (a) ispoly-D-lactide-polybutadiene (PDLA-PB) block copolymer and the at leastone second polymer (b) is poly-D-lactide, preferably wherein thecomposition comprises 1 to 60% by weight of said first polymer (a) basedon the total weight of the composition; for example from 1% to 55% byweight, for example from 2% to 55% by weight, for example from 2% to 50%by weight, for example from 3% to 50% by weight, for example from 4% to55% by weight, for example from 4% to 50% by weight, for example from 5%to 55% by weight, for example preferably from 5% to 52% by weight, forexample from 5% to 50% by weight, for example preferably from 10% to 55%by weight, for example from 10% to 50% by weight, preferably from 15% to55% by weight, for example from 20% to 55% by weight of said at leastone first polymer (a) based on the total weight of the composition.

In a preferred embodiment, said at least one first polymer (a) ispoly-D-lactide-polybutadiene (PDLA-PB) block copolymer and the at leastone second polymer (b) is poly-D-lactide, and the composition comprisesfrom 20% to 50% by weight, for example from 20% to 45% by weight, forexample from 25% to 50% by weight, for example from 25% to 45% by weightof said at least one first polymer (a) based on the total weight of thecomposition.

In an embodiment, said at least one first polymer ispolylactide-urethane-polybutadiene block copolymer.

Polylactide-urethane-polybutadiene block copolymer, can be prepared bycontacting a lactide (such as L-lactide, D-lactide, LD-lactide,meso-lactide or a mixture thereof) with a polybutadiene, preferably ahydroxy functionalized polybutadiene, thereby obtainingpolylactide-polybutadiene block copolymer, and contacting said blockcopolymer with a diisocyanate compound and optionally a diamine or adialcohol to form a polylactide-urethane-polybutadiene block copolymer.The dihydroxyl alcohol or diamine can be used as initiator.Poly-L-lactide-urethane-polybutadiene block copolymer,poly-D-lactide-urethane-polybutadiene block copolymer,poly-DL-lactide-urethane-polybutadiene block copolymer,poly-meso-lactide-urethane-polybutadiene block copolymer, can berespectively prepared by contacting an L-lactide, D-lactide, DL-lactide,or meso-lactide, respectively, with a polybutadiene, preferably ahydroxy functionalized polybutadiene, thereby obtainingpolylactide-polybutadiene block copolymer, and contacting said blockcopolymer with a diisocyanate compound and optionally a diamine or adialcohol to form a poly-L-lactide urethane-polybutadiene blockcopolymer. The dihydroxyl alcohol or diamine can be used as initiator.

Non-limiting examples of suitable diamine initiators include1,4-diaminobutane, 1,6-diaminohexane, 1,4-diaminocyclohexane,1,4-diaminophenyl, 4,4′-diaminodiphenylmethane. Preferably, the1,4-diaminophenyl, 4,4′-diaminodiphenylmethane is used.

The following alcohols can be used as initiator: 1,3-propanediol,1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,7-heptanediol,1,8-octanediol, xylene glycol.

Suitable diisocyanate compounds include compounds of formula:O═C=N-L¹-N═C=O wherein L¹ can be aliphatic or aromatic. Preferably L¹ isselected from the group comprising C₄₋₂₀alkylene, C₄₋₆cycloalkylene,C₆₋₁₂arylene, C₆₋₁₂arylene-C₆₋₁₂arylene, C₆₋₁₂arylene C₁₋₆alkyleneC₆₋₁₂arylene, C₄₋₆cycloalkylene C₁₋₆alkylene C₄₋₆cycloalkylene; eachgroup being optionally substituted. For example L¹ can be hexamethylene,dicyclohexylmethane, diphenylmethane and the like,

Non-limiting examples of suitable diisocyanates which may be usedinclude aliphatic isocyanates such as hexamethylene diisocyanate; andaromatic isocyanates such as diphenylmethane diisocyanate (MDI) in theform of its 2,4′, 2,2′ and 4,4′ isomers and mixtures thereof, themixtures of diphenylmethane diisocyanates (MDI) and oligomers thereof,m- and p-phenylene diisocyanate, tolylene-2,4- andtolylene-2,6-diisocyanate (also known as toluene diisocyanate) in anysuitable isomer mixture, chlorophenylene-2,4-diisocyanate,naphthylene-1,5-diisocyanate, diphenylene-4,4′-diisocyanate,4,4′-diisocyanate-3,3′-dimethyl-diphenyl,3-methyl-diphenylmethane-4,4′-diisocyanate and diphenyl etherdiisocyanate; and cycloaliphatic diisocyanates such as cyclohexane-2,4-and -2,3-diisocyanate, 1-methylcyclohexyl-2,4- and -2,6-diisocyanate andmixtures thereof and bis-(isocyanatocyclohexyl)methane (e.g.4,4′-diisocyanatodicyclohexylmethane (H12MD1)), isophorone diisocyanate(IPDI), butylene diisocyanate, trimethylhexamethylene diisocyanate,isocyanatomethyl-1,8-octane diisocyanate, tetramethylxylene diisocyanate(TMXDI), 1,4-cyclohexanediisocyanate (CDI), and tolidine diisocyanate(TODD; any mixture thereof.

The present composition also comprises at least one second polymer (b)selected from the group comprising, consisting essentially of, orconsisting of polylactide, polylactide-urethane, and mixture thereof.

The composition may comprise from 40 to 99% by weight of said secondpolymer (b) based on the total weight of the composition. For example,the composition may comprise 45 to 98% by weight of said second polymer(b) based on the total weight of the composition; for example from 45%to 97% by weight, for example from 50% to 97% by weight, for examplefrom 45% to 95% by weight, for example from 50% to 95% by weight, forexample from 45% to 90% by weight, for example from 50% to 90% byweight, for example from 45% to 85% by weight, for example from 50% to85% by weight, for example from 45% to 80% by weight, for example from45% to 70% by weight, for example from 45% to 60% by weight, for examplefrom 45% to 55% by weight of said at least one second polymer (b) basedon the total weight of the composition.

In a preferred embodiment, the composition comprises from 50% to 80% byweight, for example from 50% to 70% by weight, for example from 50% to60% by weight, for example from 50% to 55% by weight of said at leastone second polymer (b) based on the total weight of the composition.

As used herein, the terms “polylactic acid” or “polylactide” or “PLA”are used interchangeably and refer to poly(lactic acid) polymerscomprising repeat units derived from lactic acid.

Polylactic acid suitable for the composition can be prepared accordingto any method known in the state of the art. The polylactic acid can beprepared by ring-opening polymerization of raw materials having requiredstructures selected from lactide, which is a cyclic dimer of lacticacid, glycolide, which is a cyclic dimer of glycolic acid, andcaprolactone and the like. Lactide includes L-lactide, which is a cyclicdimer of L-lactic acid, D-lactide, which is a cyclic dimer of D-lacticacid, meso-lactide, which is a cyclic dimer of D-lactic acid andL-lactic acid, and DL-lactide, which is a racemate of D-lactide andL-lactide. Random copolymers made from meso-lactide result in an atacticprimary structure referred to as poly(meso-lactide) and are amorphous.Random optical copolymers made from equimolar amounts of D-lactide andL-lactide are referred to as poly-DL-lactide (PDLLA) orpoly(rac-lactide) and are also amorphous.

The polylactic acid for use in the present composition also includescopolymers of lactic acid. For instance, copolymers of lactic acid andtrimethylene carbonate according to EP 11167138 and copolymers of lacticacid and urethanes according to WO 2008/037772 and PCT applicationnumber PCT/EP2011/057988. Copolymeric components other than lactic acidmay be used and include dicarboxylic acid, polyhydric alcohol,hydroxycarboxylic acid, lactone, or the like, which have two or morefunctional groups each capable of forming an ester bonding. These are,for example, polyester, polyether, polycarbonate, or the like which havethe two or more unreacted functional groups in a molecule. Thehydroxycarboxylic acids may be selected from the list comprisingglycolic acid, hydroxybutyric acid, hydroxyvaleric acid,hydroxypentanoic acid, hydroxycaproic acid, and hydroxyheptanoic acid.In an embodiment no comonomer is used.

The poly-lactide suitable for the composition can be amorphouspoly-lactide. As used herein, the term “amorphous” refers to a solidthat is non-crystalline and lacks the long-range order characteristicsof a crystal. For poly-lactide, the polymerization of a racemic mixtureof L- and D-lactides usually leads to the synthesis of poly-DL-lactidethat is amorphous. When non-racemic mixtures are being polymerized, thedegree of crystallinity of the resulting polymer may be controlled bythe ratio of D to L enantiomers used and/or the type of catalyst usedduring the polymerization reaction.

Suitable PLLA (poly-L-lactide) for use in the invention can comprise theproduct of a co-polymerization reaction of mainly L-lactides (orL,L-lactides) with some D lactide units. The PLLA (poly-L-lactide)suitable for the invention may comprise a content of D isomer of atleast 10% by weight based on the total weight of the PLLA. Preferably,the PLLA comprises a content of D isomer of at least 20% by weight basedon the total weight of the PLLA. More preferably, the PLLA comprises acontent of D isomer of at least 25% by weight based on the total weightof the PLLA.

Suitable PDLA (poly-D-lactide) for use in the present invention maycomprise the product of a co-polymerization reaction of mainlyD-lactides (or D,D-lactides) with some L lactide units. The PDLA(poly-L-lactide) suitable for the invention may comprise a content of Lisomer of at least 10% by weight based on the total weight of the PDLA.Preferably, the PDLA comprises a content of L isomer of at least 20% byweight based on the total weight of the PDLA. More preferably, the PDLAcomprises a content of L isomer of at least 30% by weight based on thetotal weight of the PDLA.

Suitable PDLLA (poly-DL-lactide) for use in the present invention maycomprise the product of a polymerization reaction of a racemic mixtureof D-lactide and L-lactide. Suitable poly(meso)lactide for use in thepresent invention may comprise the product of a polymerization reactionof meso-lactide.

The D/L isomer content of PLA can be measured by different techniques,such as NMR, polarimetry or by enzymatic method or GCMS. Preferably, theD/L isomer content is measured by enzymatic method and/or NMR, asdescribed for herein below. Enzymatic method: The stereochemical purityof the PLLA or of the PDLA can be determined from the respective contentof L-mer or of D-mer. The terms “content of D-mer” and “content ofL-mer” refer respectively to the monomer units of type D and of type Lthat occur in polylactide, using the enzymatic method. The principle ofthe method is as follows: The L-lactate and D-lactate ions are oxidizedto pyruvate respectively by the enzymes L-lactate dehydrogenase andD-lactate dehydrogenase using nicotinamide-adenine dinucleotide (NAD) ascoenzyme. To force the reaction in the direction of formation ofpyruvate, it is necessary to trap this compound by reaction withhydrazine. The increase in optical density at 340 nm is proportional tothe amount of L-lactate or of D-lactate present in the sample. Thesamples of PLA can be prepared by mixing 25 ml of sodium hydroxide (1mol/L) with 0.6 g of PLA. The solution was boiled for 8 h and thencooled. The solution was then adjusted to neutral pH by addinghydrochloric acid (1 mol/L), then deionized water was added in asufficient amount to give 200 ml. The samples were then analyzed on aVital Scientific Selectra Junior analyzer using, for L-mer determinationof poly-L-lactide acid, the box titled “L-lactic acid 5260” marketed bythe company Scil and for D-mer determination of poly-D-lactide acid, thebox titled “L-lactic acid 5240” marketed by the company Scil. During theanalysis, a reactive blank and calibration using the calibrant “Scil5460” are used. The presence of insertion and racemization defects canalso be determined by carbon-13 nuclear magnetic resonance (NMR)(Avance, 500 MHz, 10 mm SELX probe). The samples can be prepared from250 mg of PLA dissolved in 2.5 to 3 ml of CDCl₃.

PLA suitable for the invention can have high molecular weights. In apreferred embodiment, the PLA has a weight average molecular weight (Mw)of at least 40 kDa, preferably at least 100 kDa, for example at least150 kDa. Measurement of the molecular masses may be performed at 25° C.using a liquid chromatograph WATERS 610. Firstly, a polymer solution isprepared in chloroform (1 mg polymer/ml). Then, 100 μl of this solutionis taken and injected, through a filter (with pores of 0.2 μm diameter,on the chromatograph column at 25° C. Molecular masses are determinedfrom the retention time in the column, translated in mass equivalentusing a universal calibration law based on polystyrene standards. Forexample, ASTM practice D3016-97(2010) may be used. In an embodiment, theratio of the weight average molecular weight (Mw) to the number averagemolecular weight (Mn) is generally from 1.0 to 5.0.

Preferably, PLA suitable the invention, has a number average molecularweight (Mn) ranging from 40000 to 350000 g/mol, more preferably from50000 to 175000 g/mol, even more preferably from 60000 to 150000 g/mol.The weight average and number average molecular weight were measured bychromatography by gel permeation compared to a polystyrene standard inchloroform at 25° C.

In an embodiment, the PLA may have a density of from 1.228 g/cm³ to1.269 g/cm³, for example from 1.230 g/cm³ to 1.260 g/cm³, for examplefrom 1.235 g/cm³ to 1.255 g/cm³ as determined in accordance with ASTMD792.

In an embodiment, the polylactic acid may exhibit a melt flow rateranging from 1 to 100 g/600 s, preferably 2 to 50 g/600 s, for example 3to 12 g/600 s, wherein the Melt Flow Rate is measured according to ISO1133 at 190° C. under a load of 2.16 kg.

For example, a process for preparing PLA and/or PLA suitable for theinvention comprises the step of contacting at least one lactide, with asuitable catalyst, and optionally in the presence of a co-initiator. Theprocess may be performed with or without solvent.

The catalyst employed by the process may have general formula M(Y¹,Y², .. . Y^(P))_(q), in which M is a metal selected from the group comprisingthe elements of columns 3 to 12 of the periodic table of the elements,as well as the elements Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Ca, Mg and Bi;whereas Y¹, Y², . . . Y^(P) are each substituents selected from thegroup comprising alkyl with 1 to 20 carbon atoms, aryl having from 6 to30 carbon atoms, alkoxy having from 1 to 20 carbon atoms, aryloxy havingfrom 6 to 30 carbon atoms, and other oxide, carboxylate, and halidegroups as well as elements of group 15 and/or 16 of the periodic table;p and q are integers of from 1 to 6. As examples of suitable catalysts,we may notably mention the catalysts of Sn, Ti, Zr, Zn, and Bi;preferably an alkoxide or a carboxylate and more preferably Sn(Oct)₂,Ti(OiPr)₄, Ti(2-ethylhexanoate)₄, Ti(2-ethylhexyloxide)₄, Zr(OiPr)₄,Bi(neodecanoate)₃,(2,4-di-tert-butyl-6-(((2-(dimethylamino)ethyl)(methyl)amino)methyl)phenoxy)(ethoxy)zinc,or Zn(lactate)₂.

In an embodiment, the PLLA and/or PDLA suitable for the invention can beobtained by polymerizing (such as L-lactide, D-lactide, LD-lactide,meso-lactide or a mixture thereof), preferably in the presence of aco-initiator of formula (IV),R¹⁰—OH  (IV)wherein R¹⁰ is selected from the group consisting of C₁₋₂₀alkyl,C₆₋₃₀aryl, and C₆₋₃₀aryl C₁₋₂₀alkyl optionally substituted by one ormore substituents selected from the group consisting of halogen,hydroxyl, and C₁₋₆alkyl. Preferably, R¹⁰ is selected from C₃₋₁₂alkyl,C₆₋₁₀aryl, and C₆₋₁₀aryl C₃₋₁₂alkyl, optionally substituted by one ormore substituents, each independently selected from the group consistingof halogen, hydroxyl, and C₁₋₆alkyl; preferably, R¹⁰ is selected fromC₃₋₁₂alkyl, C₆₋₁₀aryl, and C₆₋₁₀aryl C₃₋₁₂alkyl, optionally substitutedby one or more substituents, each independently selected from the groupconsisting of halogen, hydroxyl and C₁₋₄alkyl. The initiator can be analcohol. The alcohol can be a polyol such as diol, triol or higherfunctionality polyhydric alcohol. The alcohol may be derived frombiomass such as for instance glycerol or propanediol or any othersugar-based alcohol such as for example erythritol. The alcohol can beused alone or in combination with another alcohol.

In an embodiment, non-limiting examples of initiators include 1-octanol,isopropanol, propanediol, trimethylolpropane, 2-butanol, 3-buten-2-ol,1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,7-heptanediol, benzylalcohol, 4-bromophenol, 1,4-benzenedimethanol, and(4-trifluoromethyl)benzyl alcohol; preferably, said compound of formula(IV) is selected from 1-octanol, isopropanol, and 1,4-butanediol.

The polymerization can be performed at a temperature of 60° C.-200° C.The temperature is preferably that of the reaction itself. According toan embodiment, without solvent, the polymerization can be performed at atemperature of 110° C.-190° C. in bulk.

In an embodiment, the at least one second polymer (b) can bepolylactide-polyurethane. Non-limiting examples of suitablepolylactide-urethanes are described in WO2010/133419 hereby incorporatedby reference.

Preferably, the composition comprises:

(a) polylactide-polybutadiene (PLA-PB) block copolymer and (b)polylactide; preferably wherein the composition comprises from 40 to 99%by weight of said polylactide (b) based on the total weight of thecomposition; for example from 45% to 98% by weight; for example from 45%to 97% by weight, for example from 50% to 97% by weight, for examplefrom 45% to 95% by weight, for example from 50% to 95% by weight, forexample from 45% to 90% by weight, for example from 50% to 90% byweight, for example from 45% to 85% by weight, for example from 50% to85% by weight, for example from 45% to 80% by weight, for example from50% to 80% by weight, for example from 45% to 70% by weight, for examplefrom 50% to 70% by weight, for example from 45% to 75% by weight, forexample from 50% to 75% by weight of said polylactide (b) based on thetotal weight of the composition.

Preferably, the composition comprises: (a) polylactide-polybutadiene(PLA-PB) block copolymer and (b) polylactide; preferably wherein thecomposition comprises from 50 to 80% by weight of said polylactide (b)based on the total weight of the composition; for example from 50% to70% by weight, for example from 50% to 75% by weight of said polylactide(b) based on the total weight of the composition.

For example, the composition can comprise:

(a) poly-L-lactide-polybutadiene (PLLA-PB) block copolymer, and (b)poly-L-lactide; preferably wherein the composition comprises from 40 to99% by weight of said poly-L-lactide (b) based on the total weight ofthe composition; for example from 45% to 98% by weight; for example from45% to 97% by weight, for example from 50% to 97% by weight, for examplefrom 45% to 95% by weight, for example from 50% to 95% by weight, forexample from 45% to 90% by weight, for example from 50% to 90% byweight, for example from 45% to 85% by weight, for example from 50% to85% by weight, for example from 45% to 80% by weight, for example from50% to 80% by weight, for example from 45% to 70% by weight, for examplefrom 50% to 70% by weight, for example from 45% to 75% by weight, forexample from 50% to 75% by weight of said poly-L-lactide (b) based onthe total weight of the composition.

Preferably, the composition comprises: (a) poly-L-lactide-polybutadiene(PLLA-PB) block copolymer, and (b) poly-L-lactide; preferably whereinthe composition comprises from 50 to 80% by weight of saidpoly-L-lactide (b) based on the total weight of the composition; forexample from 50% to 70% by weight, for example from 50% to 75% by weightof said poly-L-lactide (b) based on the total weight of the composition.

For example, the composition can comprise:

(a) poly-D-lactide-polybutadiene (PDLA-PB) block copolymer, and (b)poly-D-lactide; preferably wherein the composition comprises from 40 to99% by weight of said poly-D-lactide (b) based on the total weight ofthe composition; for example from 45% to 98% by weight; for example from45% to 97% by weight, for example from 50% to 97% by weight, for examplefrom 45% to 95% by weight, for example from 50% to 95% by weight, forexample from 45% to 90% by weight, for example from 50% to 90% byweight, for example from 45% to 85% by weight, for example from 50% to85% by weight, for example from 45% to 80% by weight, for example from50% to 80% by weight, for example from 45% to 70% by weight, for examplefrom 50% to 70% by weight, for example from 45% to 75% by weight, forexample from 50% to 75% by weight of said poly-D-lactide (b) based onthe total weight of the composition.

Preferably, the composition comprises: (a) poly-D-lactide-polybutadiene(PDLA-PB) block copolymer, and (b) poly-D-lactide; preferably whereinthe composition comprises from 50 to 80% by weight of saidpoly-D-lactide (b) based on the total weight of the composition; forexample from 50% to 70% by weight, for example from 50% to 75% by weightof said poly-D-lactide (b) based on the total weight of the composition.

For example, the composition can comprise:

(a) polylactide-polybutadiene (PLA-PB) block copolymer and (b)polylactide, wherein the composition comprises 1 to 60% by weight ofsaid polylactide-polybutadiene block copolymer (a) based on the totalweight of the composition; for example from 1% to 55% by weight, forexample from 2% to 55% by weight, for example from 2% to 50% by weight,for example from 3% to 50% by weight, for example from 4% to 55% byweight, for example from 4% to 50% by weight, for example from 5% to 55%by weight, for example preferably from 5% to 52% by weight, for examplefrom 5% to 50% by weight, for example preferably from 10% to 55% byweight, for example from 10% to 50% by weight, preferably from 15% to55% by weight, for example from 20% to 55% by weight, for example from20% to 50% by weight, for example from 20% to 45% by weight, for examplefrom 25% to 50% by weight, for example from 25% to 45% by weight of saidpoly-lactide-polybutadiene block copolymer (a) based on the total weightof the composition; and preferably wherein the composition comprisesfrom 50 to 98% by weight of said polylactide (b) based on the totalweight of the composition; for example from 45% to 98% by weight; forexample from 45% to 97% by weight, for example from 50% to 97% byweight, for example from 45% to 95% by weight, for example from 50% to95% by weight, for example from 45% to 90% by weight, for example from50% to 90% by weight, for example from 45% to 85% by weight, for examplefrom 50% to 85% by weight, for example from 45% to 80% by weight, forexample from 50% to 80% by weight, for example from 45% to 70% byweight, for example from 50% to 70% by weight, for example 45% to 75% byweight, for example from 50% to 75% by weight of said polylactide (b)based on the total weight of the composition.

Preferably, the composition comprises: (a) polylactide-polybutadiene(PLA-PB) block copolymer and (b) polylactide, wherein the compositioncomprises 20 to 50% by weight of said polylactide-polybutadiene blockcopolymer (a) based on the total weight of the composition; for examplefrom 20% to 45% by weight, for example from 25% to 50% by weight, forexample from 30% to 50% by weight, for example from 25% to 45% by weightof said poly-lactide-polybutadiene block copolymer (a) based on thetotal weight of the composition; and preferably wherein the compositioncomprises from 50 to 80% by weight of said polylactide (b) based on thetotal weight of the composition; for example from 55% to 80% by weight,for example from 50% to 70% by weight, for example from 50% to 75%, forexample from 55% to 75% by weight by weight of said polylactide (b)based o n the total weight of the composition.

For example, the composition can comprise:

(a) poly-L-lactide-polybutadiene (PLLA-PB) block copolymer, and (b)poly-L-lactide; preferably wherein the composition comprises 1 to 60% byweight of said poly-L-lactide-polybutadiene block copolymer (a) based onthe total weight of the composition; for example from 1% to 55% byweight, for example from 2% to 55% by weight, for example from 2% to 50%by weight, for example from 3% to 50% by weight, for example from 4% to55% by weight, for example from 4% to 50% by weight, for example from 5%to 55% by weight, for example preferably from 5% to 52% by weight, forexample from 5% to 50% by weight, for example preferably from 10% to 55%by weight, for example from 10% to 50% by weight, preferably from 15% to55% by weight, for example from 20% to 55% by weight, for example from20% to 50% by weight, for example from 20% to 45% by weight, for examplefrom 25% to 50% by weight, for example from 25% to 45% by weight of saidpoly-L-lactide-polybutadiene block copolymer (a) based on the totalweight of the composition; and preferably wherein the compositioncomprises from 40% to 99% by weight of said poly-L-lactide (b) based onthe total weight of the composition; for example from 45% to 98% byweight; for example from 45% to 97% by weight, for example from 50% to97% by weight, for example from 45% to 95% by weight, for example from50% to 95% by weight, for example from 45% to 90% by weight, for examplefrom 50% to 90% by weight, for example from 45% to 85% by weight, forexample from 50% to 85% by weight, for example from 45% to 80% byweight, for example from 50% to 80% by weight, for example from 45% to70% by weight, for example from 50% to 70% by weight, for example 45% to75% by weight, for example from 50% to 75% by weight of saidpoly-L-lactide (b) based on the total weight of the composition.

Preferably, the composition comprises: (a) poly-L-lactide-polybutadiene(PLLA-PB) block copolymer, and (b) poly-L-lactide; preferably whereinthe composition comprises 20 to 50% by weight of saidpoly-L-lactide-polybutadiene block copolymer (a) based on the totalweight of the composition; for example from 20% to 45% by weight, forexample from 25% to 50% by weight, for example from 30% to 50% byweight, for example from 25% to 45% by weight of saidpoly-L-lactide-polybutadiene block copolymer (a) based on the totalweight of the composition; and preferably wherein the compositioncomprises from 50% to 80% by weight of said poly-L-lactide (b) based onthe total weight of the composition; for example from 55% to 80% byweight, for example from 50% to 70% by weight, for example from 50% to75% by weight, for example from 55% to 75% by weight of saidpoly-L-lactide (b) based on the total weight of the composition.

For example, the composition can comprise:

(a) poly-D-lactide-polybutadiene (PDLA-PB) block copolymer, and (b)poly-D-lactide; preferably wherein the composition comprises 1 to 60% byweight of said poly-D-lactide-polybutadiene block copolymer (a) based onthe total weight of the composition; for example from 1% to 55% byweight, for example from 2% to 55% by weight, for example from 2% to 50%by weight, for example from 3% to 50% by weight, for example from 4% to55% by weight, for example from 4% to 50% by weight, for example from 5%to 55% by weight, for example preferably from 5% to 52% by weight, forexample from 5% to 50% by weight, for example preferably from 10% to 55%by weight, for example from 10% to 50% by weight, preferably from 15% to55% by weight, for example from 20% to 55% by weight, for example from20% to 50% by weight, for example from 20% to 45% by weight, for examplefrom 25% to 50% by weight, for example from 25% to 45% by weight of saidpoly-D-lactide-polybutadiene block copolymer (a) based on the totalweight of the composition; and preferably wherein the compositioncomprises from 40% to 99% by weight of said poly-D-lactide (b) based onthe total weight of the composition; for example from 45% to 98% byweight; for example from 45% to 97% by weight, for example from 50% to97% by weight, for example from 45% to 95% by weight, for example from50% to 95% by weight, for example from 45% to 90% by weight, for examplefrom 50% to 90% by weight, for example from 45% to 85% by weight, forexample from 50% to 85% by weight, for example from 45% to 80% byweight, for example from 50% to 80% by weight, for example from 45% to70% by weight, for example from 50% to 70% by weight, for example 45% to75% by weight, for example from 50% to 75% by weight of saidpoly-D-lactide (b) based on the total weight of the composition.

Preferably, the composition comprises:

(a) poly-D-lactide-polybutadiene (PDLA-PB) block copolymer, and (b)poly-D-lactide; preferably wherein the composition comprises 20 to 50%by weight of said poly-D-lactide-polybutadiene block copolymer (a) basedon the total weight of the composition; for example from 20% to 45% byweight, for example from 25% to 50% by weight, for example from 30% to50% by weight, for example from 25% to 45% by weight of saidpoly-D-lactide-polybutadiene block copolymer (a) based on the totalweight of the composition; and preferably wherein the compositioncomprises from 50% to 80% by weight of said poly-D-lactide (b) based onthe total weight of the composition; for example from 55% to 80% byweight, for example from 50% to 70% by weight, for example from 50% to75% by weight, for example from 55% to 75% by weight of saidpoly-D-lactide (b) based on the total weight of the composition.

In an embodiment, the composition comprises:

from 1% to 60% by weight of polylactide-polybutadiene block copolymerbased on the total weight of the composition; and from 40% to 99% byweight of the second polymer (b1) based on the total weight of thecomposition.

In an embodiment, the composition comprises:

from 1% to 60% by weight of polylactide-polybutadiene block copolymerbased on the total weight of the composition; and from 40% to 99% byweight of polylactide (b) based on the total weight of the composition.

According to the second aspect, the present invention also encompasses aprocess for preparing a composition according to the present invention,comprising the step of:

contacting (a) at least one first polymer selected frompolylactide-polybutadiene (PLA-PB) block copolymer,polylactide-urethane-polybutadiene block copolymer, or a mixturethereof;

with (b) at least one second polymer selected from polylactide,polylactide-urethane, or a mixture thereof.

Any process known in the art can be applied for preparing a compositionas presently described.

In some embodiments, said contacting step comprises melt blending the atleast one first polymer with the at least one second polymer. In someembodiments, said melt blending process occurs, in a single step. Theblending may occur by introducing the first polymer and the secondpolymer, into a system capable of combining and melting the componentsto initiate chemical and/or physical interactions between the first andsecond polymer components. For example, the blending may be accomplishedby introducing the first and second polymers into a batch mixer,continuous mixer, single screw extruder or twin screw extruder, forexample, to form a homogeneous mixture or solution while providingtemperature conditions so as to melt the blend components and initiatechemical and physical interactions the first and second polymercomponents as described above.

In an embodiment, the composition is prepared by extrusion. In anembodiment, the composition is extruded at a temperature of at least140° C., for example at least 150° C., for example at least 160° C., forexample ranging from 160° C. to 230° C. More preferably, the compositionis extruded at a temperature ranging from 180° C. to 230° C.

In a preferred embodiment, said contacting step comprises meltprocessing a blend comprising polylactide-polybutadiene (PLLA-PB) blockcopolymer and polylactide.

In an embodiment, said contacting step comprises melt processing a blendcomprising poly-L-lactide-polybutadiene (PLLA-PB) block copolymer andpoly-L-lactide.

In an embodiment, said contacting step comprises melt processing a blendcomprising poly-L-lactide-polybutadiene (PDLA-PB) block copolymer andpoly-D-lactide.

In a preferred embodiment, the residence time in the extruder is at most30 minutes, more preferably at most 20 minutes, more preferably at most10 minutes, more preferably at most 8 minutes, more preferably at most 5minutes. As used herein, the term “residence time” refers to the timewherein the mixture is present in the extruder, or is present in aseries of extruders.

In an embodiment, any of the previously described compositions mayfurther comprise additives to impart desired physical properties, suchas printability, increased gloss, or a reduced blocking tendency.Examples of additives may include, without limitation, stabilizers,ultra-violet screening agents, oxidants, anti-oxidants, antistaticagents, ultraviolet light absorbents, fire retardants, processing oils,mold release agents, coloring agents, pigments/dyes, fillers orcombinations thereof, for example. These additives may be included inamounts effective to impart desired properties.

In some embodiments, said process for preparing a composition accordingto the present invention, further comprises processing the compositionusing one or more polymer processing techniques selected from film,sheet, pipe and fiber extrusion or coextrusion; blow molding; injectionmolding; rotary molding; foaming; 3D printing, and thermoforming.

The present invention is also directed towards the use ofpolylactide-polybutadiene block copolymer,polylactide-urethane-polybutadiene block copolymer, or a mixturethereof; as impact modifier to improve melt strength and impact strengthfor PLA.

The present invention also encompasses the use ofpolylactide-polybutadiene block copolymer,polylactide-urethane-polybutadiene block copolymer, or mixtures thereofas impact modifier for polymers.

The compositions of the invention were found to have greatly improvedthe impact properties over the polylactide alone.

The present invention also encompasses polymers, membranes, adhesives,foams, sealants, molded articles, films, extruded articles, fibers,elastomers, composite material, adhesives, organic LEDs, organicsemiconductors, and conducting organic polymers, 3D printed articles,comprising the composition according to the present invention.

The present invention also encompasses an article comprising acomposition according to any of the embodiments previously described forthe present invention, or prepared using a process according to theinvention.

In some embodiments, said article comprising a composition according toany of the embodiments previously described for the present invention,or prepared using a process according to the invention; is a shapedarticle.

In some embodiments, said shaped article comprising a compositionaccording to any of the embodiments previously described for the presentinvention, or prepared using a process according to the invention; is amolded article.

In an embodiment, said shaped article is produced by polymer processingtechniques known to one of skill in the art, such as blow molding,injection molding, rotary molding, compression molding; 3D printing, andthermoforming.

In an embodiment, the compositions and blends thereof may be formed intoa wide variety of articles such as films, pipes, fibers (e.g., dyeablefibers), rods, containers, bags, packaging materials, 3D printedarticles, and adhesives (e.g., hot melt adhesives) for example, bypolymer processing techniques known to one of skill in the art, such asforming operations including film, sheet, pipe and fiber extrusion andco-extrusion as well as blow molding, injection molding, rotary molding,3D printing, and thermoforming, for example. Films include blown,oriented or cast films formed by extrusion or co-extrusion or bylamination useful as shrink film, cling film, stretch film, sealingfilms, oriented films, snack packaging, heavy duty bags, grocery sacks,baked and frozen food packaging, medical packaging, industrial liners,and membranes, for example, in food-contact and non-food contactapplication. Fibers include slit-films, monofilaments, melt spinning,solution spinning and melt blown fiber operations for use in woven ornon-woven form to make sacks, bags, rope, twine, carpet backing, carpetyarns, filters, diaper fabrics, medical garments and geotextiles, forexample. Extruded articles include medical tubing, wire and cablecoatings, hot melt adhesives, sheets, such as thermoformed sheets(including profiles and plastic corrugated cardboard), geomembranes andpond liners, for example. Molded articles include single andmultilayered constructions in the form of bottles, tanks, large hollowarticles, rigid food containers and toys, for example.

The present invention can be further illustrated by the followingexamples, although it will be understood that these examples areincluded merely for purposes of illustration and are not intended tolimit the scope of the invention unless otherwise specificallyindicated.

EXAMPLES

Unless otherwise indicated, all parts and all percentages in thefollowing examples, as well as throughout the specification, are partsby weight or percentages by weight respectively.

Example 1 Preparation of Poly-L-Lactide-Polybutadiene (PLLA-PB) BlockCopolymer

PLLA-PB-PLLA block copolymer was prepared by reacting hydroxy terminatedpolybutadiene (Krasol®LBH10000 from HSC Cray Valley Corp) with L-lactidein bulk, in the presence of a catalyst to prepare the copolymer.Krasol®LBH10000 from HSC Cray Valley Corp, had the following properties:Microstructure: 1,2-(vinyl): about 65 wt %, 1,4-cis: about 18 wt %;1,4-trans: about 17 wt %; Content of OH groups 0.16-0.22 (Mmol/g),Hydroxyl number 8.9-12.4 Mg KOH/g, Viscosity Brookfield 20-50 Pa·s at50° C. Density: about 0.9 g/cm³ at 20° C.; Molecular weight (Mn):9000-11000 g/mol; Polydispersity Index (Mw/Mn): 1.1. Purified L-Lactidefrom Futerro optical purity above 99.5% was used. Hydroxy terminatedpolybutadiene (7.78 g) and L-lactide (8.0 g) were heated to 185° C.under N₂ until a clear mixture was obtained. Sn(Oct)₂ (112 mg) wasadded. Polymerization was carried out for 30 min and the product (blockcopolymer 1) was precipitated in ethanol.

The modulus of the copolymer was measured as described in ISO 527-1BA.The result is shown in Table 1, and compared with the modulus for PLA(PLLA (NatureWorks® PLA polymer 6201D).

TABLE 1 Modulus on PLLA-PB-PLLA copolymer (tensile-20 mm/min-100%/min)at 23° C. PB HO-PB- Con- Mn quantity OH (Mn) version theoretic HazeModulus Example % g · mol⁻¹ % g · mol⁻¹ % Mpa PLA6201 0 <10 3260 Copol-52 10.000 95 19.250 <10 20 ymer 1

Example 2

Compositions 1 and 2 according to an embodiment of the invention wereprepared by blending PLLA (Synterra® PLLA 2010 from Synbra technologyb.v) with PLLA-PB-PLLA block copolymer 1 prepared in example 1. Thephysical properties of Synterra® PLLA 2010 are shown in Table 2.Comparative composition 3 is prepared by blending PLLA (Synterra® PLLA2010 from Synbra technology b.v) with PLLA-PB-PLLA block copolymer 1prepared in example 1. Comparative composition 4 consisted of pure PLLA(Synterra® PLLA 2010 from Synbra technology b.v).

TABLE 2 PHYSICAL PROPERTIES TEST METHOD UNITS SPECIFICATION Appearanceround pellets Color Off white (crystallized) Melt Flow Rate ISO 1133g/600 s 4 (+−2) (190° C./2.16 kg) Polymer Density ISO 1183 g/cm³ 1.25Moisture content <400 ppm Residual Monomer % <0.5 D-Isomer % <1 Meltingtemperature DSC: ISO 11357 ° C. 175-180 Glass Transition DSC: ISO 11357° C. 55-60 temperature

PLLA pellets were dried in a dryer for 1 hour at 110° C. The recipes ofthe compositions are shown in Table 3.

TABLE 3 PLLA 2010 PLLA-PB-PLLA Block Compositions (wt %) copolymer 1 (wt%) Composition 1 70 30 Composition 2 60 40 Comparative composition 3 9010 Comparative composition 4 100 0

Composition 1 was melt blended in a (Haake) counter-rotating twin screwmini-extruder, at 4 bars, 200° C., 100 rpm and a residence time of 3 minfor 5 passes.

Composition 2 was melt blended in a (Haake) counter-rotating twin screwmini-extruder, at 190° C., 50 rpm and a residence time of 5 min.

Composition 3 is melt blended in a (Haake) counter-rotating twin screwmini-extruder, at 4 bars, 200° C., 100 rpm and a residence time of 3 minfor 5 passes.

Composition 4 was melt blended in a (Haake) counter-rotating twin screwmini-extruder, at 190° C., 50 rpm and a residence time of 5 min.

Thermal properties of composition 2 were analyzed with Perkin-ElmerPyris Diamond differential scanning calorimeter (DSC) calibrated withindium as standard. The specimen was heated from 25 to 240° C. at a rateof 20° C./min, under N₂, followed by an isothermal at 240° C. for 3 min,and a subsequent cooling scan to 25° C. at a rate of 20° C./min. Andthen were reheated to 240° C. at 20° C./min. Glass transitiontemperature (Tg), melting temperature (Tm) and the enthalpy of melting(ΔHm) were measured. The DSC thermogram of the composition 2 ispresented in FIG. 1.

Mechanical properties of the compositions were investigated by Izodimpact tester. Un-notched Izod impact was measured at 23° C. accordingto IS0180. Unnotched test specimen 9.99 mm×4.21 mm (section 42.1 mm²) isheld as a vertical cantilevered beam and is impacted at 3.5 m/s by aswinging pendulum (5.5 J).

The results are shown in Table 4.

TABLE 4 Compositions Un-notched Izod (kJ/m²) Composition 1 NDComposition 2 73.8 Composition 3 15-20 Composition 4 15 ND: notdetermined

Comparative compositions comprising poly-L-lactide identified below asPLA 6201 (Ingeo™ 6201D from NatureWorks LLC) or PLA 2002D (fromNatureWorks LLC), optionally in the presence of commercial impactmodifiers were tested. The physical properties of PLA 6201D and PLA2002D are shown in Table 5. As impact modifier either Opaque ImpactModifier BioStrength® 150 or Transparent acrylic core shell impactmodifier BioStrength® 280 from Arkema were used.

TABLE 5 Physical Properties ASTM method Ingeo 6201D Specific Gravity1.24 D792 Relative Viscosity 3.1 CD internal Viscotek Method Melt Index,g/10 min (210° C.) 15-30 D1238 Melt Density (230° C.) 1.08 GlassTransition Temperature (° C.) 55-60 D3417 Crystalline Melt Temperature(° C.) 155-170 D3418 D-isomer (%) 1.4 PLA Polymer 2002D Specific Gravity1.24 D792 Melt Index, g/10 min 4-8 (190° C.) D1238 Clarity TransparentMechanical Properties Tensile Strength @ Break, psi (MPa) 7,700 (53)D882 Tensile Yield Strength, psi (MPa) 8,700 (60) D882 Tensile Modulus,kpsi (GPa)  500 (3.5) D882 Tensile Elongation, % 6.0 D882 Notched IzodImpact, (J/m) 12.81 D256 D-isomer (%)   2-2.5

The mechanical properties of the compositions were investigated by Izodimpact tester, and the results are shown in Table 6. The compositionscomprising impact modifier were not transparent.

TABLE 6 Notched Unnotched (ISO180) (ISO180) Resil- Resil- Absorbed ienceAbsorbed ience Samples energy kJ/m² energy kJ/m² Neat PLA 6201 Neat PLA0.084 2.5 0.6 14.6 PLA 2002 + 2%  2% BS 150 0.099 2.9 0.83 19.9Biostrength ® 150 PLA 6201 + 5%  5% BS 150 0.117 3.667 1.138 27.6Biostrength ® 150 PLA 6201 + 10% 10% BS 150 0.276 8.7 1.751 42.6Biostrength ® 150 PLA 6201 + 15% 15% BS 150 0.820 25.57 5.487 133.5Biostrength ® 150 PLA 6201 + 5%  5% BS 280 0.115 3.60 0.881 21.4Biostrength ® 280 PLA 6201 + 10% 10% BS 280 0.194 5.90 1.395 33.9Biostrength ® 280 PLA 6201 + 15% 15% BS 280 0.227 6.90 2.232 54.2Biostrength ® 280

The invention claimed is:
 1. A process for preparing a compositioncomprising: contacting (a) at least one first polymer wherein the firstpolymer is a polylactide-urethane-polybutadiene block copolymer or amixture of a polylactide-urethane-polybutadiene block copolymer and aPLA-PB block copolymer; with (b) at least one second polymer selectedfrom polylactide, polylactide-urethane, or a mixture thereof; whereinthe composition comprises; from 20% to 50% by weight of said firstpolymer based on the total weight of the composition and from 50% to 80%by weight of said second polymer based on the total weight of thecomposition.
 2. The process according to claim 1, wherein saidcontacting step comprises melt blending the at least one first polymerwith the at least one second polymer.
 3. The process according to claim1, wherein said composition is melt blended at a temperature rangingfrom 160° C. to 230° C.
 4. The process according to claim 1, comprisingmelt blending from 25% to 50% by weight ofpolylactide-urethane-polybutadiene block copolymer or a mixture of apolylactide-urethane-polybutadiene block copolymer and a PLA-PB blockcopolymer; and from 50% to 75% by weight of the second polymer, whereinthe second polymer is polylactide.
 5. The process according to claim 1,further comprising processing the composition using one or more polymerprocessing techniques selected from film, sheet, pipe and fiberextrusion or coextrusion; blow molding; injection molding; rotarymolding; foaming; and thermoforming.